1. Technical Field
Embodiments of the present invention relate to the field of semiconductor surface processing, and particularly to a method of processing a surface of a polysilicon and a method of processing a surface of a substrate assembly.
2. Description of the Related Art
A rough part of a surface of a polysilicon formed by a current low-temperature polysilicon thin film technology exists mainly at a boundary where grains join, i.e. at a grain boundary. A mechanism of forming the rough surface can result from a difference between densities of a melted silicon and a solid silicon. A solidification process begins at a nucleation center and what is last solidified is at the grain boundary where the melted silicon and the solid silicon exist simultaneously. After a process of forming the grains is finished, a protrusion is formed at the grain boundary.
FIG. 1 shows a surface of a polysilicon formed by a typical low-temperature polysilicon technology. The surface has a roughness of up to 9 nm.